{"title":"论最大阶数为 5 的稀疏图的注入色度指数","authors":"Jian Lu, Zhen-Mu Hong, Zheng-Jiang Xia","doi":"10.1007/s10878-024-01234-7","DOIUrl":null,"url":null,"abstract":"<p>A <i>k</i>-edge coloring <span>\\(\\varphi \\)</span> of a graph <i>G</i> is injective if <span>\\(\\varphi (e_1)\\ne \\varphi (e_3)\\)</span> for any three consecutive edges <span>\\(e_1, e_2\\)</span> and <span>\\(e_3\\)</span> of a path or a triangle. The injective chromatic index <span>\\(\\chi _i'(G)\\)</span> of <i>G</i> is the smallest <i>k</i> such that <i>G</i> admits an injective <i>k</i>-edge coloring. By discharging method, we demonstrate that any graph with maximum degree <span>\\(\\Delta \\le 5\\)</span> has <span>\\(\\chi _i'(G)\\le 12\\)</span> (resp. 13) if its maximum average degree is less than <span>\\(\\frac{20}{7}\\)</span> (resp. 3), which improves the results of Zhu (2023).\n</p>","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On injective chromatic index of sparse graphs with maximum degree 5\",\"authors\":\"Jian Lu, Zhen-Mu Hong, Zheng-Jiang Xia\",\"doi\":\"10.1007/s10878-024-01234-7\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>A <i>k</i>-edge coloring <span>\\\\(\\\\varphi \\\\)</span> of a graph <i>G</i> is injective if <span>\\\\(\\\\varphi (e_1)\\\\ne \\\\varphi (e_3)\\\\)</span> for any three consecutive edges <span>\\\\(e_1, e_2\\\\)</span> and <span>\\\\(e_3\\\\)</span> of a path or a triangle. The injective chromatic index <span>\\\\(\\\\chi _i'(G)\\\\)</span> of <i>G</i> is the smallest <i>k</i> such that <i>G</i> admits an injective <i>k</i>-edge coloring. By discharging method, we demonstrate that any graph with maximum degree <span>\\\\(\\\\Delta \\\\le 5\\\\)</span> has <span>\\\\(\\\\chi _i'(G)\\\\le 12\\\\)</span> (resp. 13) if its maximum average degree is less than <span>\\\\(\\\\frac{20}{7}\\\\)</span> (resp. 3), which improves the results of Zhu (2023).\\n</p>\",\"PeriodicalId\":0,\"journal\":{\"name\":\"\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0,\"publicationDate\":\"2024-11-07\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1007/s10878-024-01234-7\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s10878-024-01234-7","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
如果对于路径或三角形的任意三条连续边\(e_1, e_2\) 和\(e_3\),图 G 的 k 边着色(\varphi \)是可注入的,那么\(\varphi (e_1)\ne \varphi (e_3)\)就是可注入的。G 的注入色度指数 \(\chi _i'(G)\)是使 G 允许注入 k 边着色的最小 k。通过放电法,我们证明了任何最大度为 \(\Delta \le 5\) 的图,如果它的最大平均度小于 \(\frac{20}{7}\) (resp.3),就有\(\chi _i'(G)\le 12\) (resp.13),这改进了 Zhu (2023) 的结果。
On injective chromatic index of sparse graphs with maximum degree 5
A k-edge coloring \(\varphi \) of a graph G is injective if \(\varphi (e_1)\ne \varphi (e_3)\) for any three consecutive edges \(e_1, e_2\) and \(e_3\) of a path or a triangle. The injective chromatic index \(\chi _i'(G)\) of G is the smallest k such that G admits an injective k-edge coloring. By discharging method, we demonstrate that any graph with maximum degree \(\Delta \le 5\) has \(\chi _i'(G)\le 12\) (resp. 13) if its maximum average degree is less than \(\frac{20}{7}\) (resp. 3), which improves the results of Zhu (2023).